/*
 * Copyright 2016-2020 The jetcd authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.etcd.jetcd;

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;

import io.etcd.jetcd.lease.LeaseGrantResponse;
import io.etcd.jetcd.lease.LeaseKeepAliveResponse;
import io.etcd.jetcd.lease.LeaseRevokeResponse;
import io.etcd.jetcd.lease.LeaseTimeToLiveResponse;
import io.etcd.jetcd.options.LeaseOption;
import io.etcd.jetcd.support.CloseableClient;
import io.grpc.stub.StreamObserver;

/**
 * Interface of KeepAlive talking to etcd.
 */
public interface Lease extends CloseableClient {

    /**
     * New a lease with ttl value.
     *
     * @param  ttl ttl value, unit seconds
     * @return     the grant response
     */
    CompletableFuture<LeaseGrantResponse> grant(long ttl);

    /**
     * New a lease with ttl value.Waits if necessary for at most the given time
     * if etcd server is available.
     *
     * @param  ttl     ttl value, unit seconds
     * @param  timeout the maximum time to waits
     * @param  unit    the time unit of the timeout argument
     * @return         The grant response
     */
    CompletableFuture<LeaseGrantResponse> grant(long ttl, long timeout, TimeUnit unit);

    /**
     * revoke one lease and the key bind to this lease will be removed.
     *
     * @param  leaseId id of the lease to revoke
     * @return         the revoke response
     */
    CompletableFuture<LeaseRevokeResponse> revoke(long leaseId);

    /**
     * keep alive one lease only once.
     *
     * @param  leaseId id of lease to keep alive once
     * @return         The keep alive response
     */
    CompletableFuture<LeaseKeepAliveResponse> keepAliveOnce(long leaseId);

    /**
     * retrieves the lease information of the given lease ID.
     *
     * @param  leaseId     id of lease
     * @param  leaseOption LeaseOption
     * @return             LeaseTimeToLiveResponse wrapped in CompletableFuture
     */
    CompletableFuture<LeaseTimeToLiveResponse> timeToLive(long leaseId, LeaseOption leaseOption);

    /**
     * keep the given lease alive forever.
     *
     * @param  leaseId  lease to be keep alive forever.
     * @param  observer the observer
     * @return          a KeepAliveListener that listens for KeepAlive responses.
     */
    CloseableClient keepAlive(long leaseId, StreamObserver<LeaseKeepAliveResponse> observer);
}
